Heat treating retort with helix

ABSTRACT

A retort for use in heating metal articles having an internal helix for moving articles in the retort while they are being heated.

United States Patent Inventor John F Sheahan Scottdale, Pa.

Appl. No. 789,708

Filed Jan. 8, 1969 Patented Jan. 19, 1971 Assignee The Duraloy Company Scottdale, Pa.

a corporation of Delaware HEAT TREATING RETORT WITH HELIX 7 Claims, 6 Drawing Figs.

Int. Cl F27b 7/08 [50] Field ofSearch 263/34; 34/108 [56] References Cited UNITED STATES PATENTS 861,235 7/1907 Huyck 263/34 3,441,259 4/1969 Heyer et al. 263/34 Primary ExaminerJ0hn J Camby Atzorney-Watts, Hoffmann, Fisher & Heinke ABSTRACT: A retort for use in heating metal articles having an internal helix for moving articles in the retort while they are being heated.

. 1 HEAT TREATING RETORT WITH HELIX BACKGROUND Prior tubular, rotatable retorts have been provided with short, spaced sections of a spiral or helical coil cast integral with the shell, or welded to the shell, of the retort.

Such retorts are costly to produce and to maintain due to the difficulty of making sound castings at the junction of the shell and coil, or of avoiding the creation of internal stresses during the welding of coil segments to the shell with resultant creation of potential causes of failure of the retort. US. Pat. No. 3,141,658 shows a retort which has short ribs welded to the inner surfaces thereof and which may possess internal stresses.

The retorts with cast in coils are subject to breakage at the junction of the shell and coils if voids or cracks are formed at the junction of the shell and ring during the casting operation and the welded-in coils created stresses which often resulted 1 in breakage. In each of these cases'repair was difficult and expensive and often was impossible.

I do not know of any prior proposal which would avoid those disadvantages.

' SUMMARY The present invention avoids the disadvantages of the prior art by providing a retort having a separately formed helical coil which is fixed in place therein by mechanical means and in which the turns of the coil may be spaced by tumblers secured to the coil.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings accompanying and forming a part hereof:

FIG. I is a longitudinal, side-elevational view, partly in section, of one form'of retort embodying the present invention;

FIG. 2 is a fragmentary, perspective view of adjacent turns of the helical coil inside the shell of FIG. 1;

FIG. 3 is an end view, partly in section, taken on line 3-3 of FIG. 2;

FIG. 4 is a fragmentary, longitudinal, sectional view showing a modified form of the helical coil and tumblers;

FIG. 5 is a fragmentary, perspective view of the helical coil of FIG. 4; and

FIG. 6 is a transverse, cross-sectional view of the retort taken on line 6-6 of FIG. 4.

FIG. 1 shows a preferred form of retort for heating solid articles, particularly metal articles which are to be-heat treated, as by carbonizing.

The retort of FIG. 1 consists of a shell I and a helical coil 3 provided with a plurality of tumblers 5.

The shell I is cylindrical and consists of a plurality of cylin drical metal castings Ia, 1b, 1c and 1d connected end to end, as by weld metal 7 and an end casting 9 connected, as by weld metal 7a, to the trailing end of section 1d of the shell. Casting 9 may serve two purposes, namely, to support one end of the retort on conventional supporting rollers and also as an inlet for gases to be used during the treatment of the solids in the retort. T-he trailing end of casting '9 is provided with a tube 11 which may be connected to a source of gas under pressure which is to be brought into contact with solids in the retort. The retort of FIG. 1 is shown provided with a ring 12 and an inlet 13 through which solids may enter the retort. This inlet 13 may be used as a bearing-engaging support for the retort when the inlet end of the retort is disposed outside of a furnace. If the retort is to be used with itsinlet end in a furnace, then the inlet 13 may be omitted. The shell I is provided with openings 15 near its discharge end to permit the discharge of articles which have passed lengthwise in the retort. The inlet end of the shell may be supported by conventional supporting rollers (not shown).

The helical coil 3 consists of a plurality of turns, indicated at 23, and a plurality of tumblers 5 connected, as by weld metal 25, to opposed surfaces of adjacent turns of the coil. If desired, turns 23 of the coil may be provided with openings 27 for the passage of gas therethrough in the interest of promoting better distribution and contact of the gases with the articles being treated. The outer edges of tumblers 5 are preferably substantially flush with the outer edges of the helical coils. The purpose of the coil 3 is to advance articles being treated from the entry end of the shell 1 to the discharge openings 15. The function of the tumblers 5 is'to carry the articles upwardly some distance along the ascending side of the shell and then to allow them to roll downwardly, thus exposing the articles to any gas which may be in the retort.

It will be understood that the tumblers 5 may be arranged within the shell 1 in various ways, for example, they may be aligned longitudinally of the shell 1 and staggered circumferentially and they may be positioned as far apart circumferentially of the shell as desired. In FIG. 3 two tumblers are spaced apart about 60 and each is spaced about from the third tumbler. It will also be understood that the tumblers 5 may be placed between adjacent turns of the coil 3 for substantially its full length if desired although none are shown in the trailing end portion of the coil.

As shown in FIGS. 1 to 3, the shell is made of several separate cylindrical castings welded together end to end but it may be made as a single casting if desired. The helical coil 3 is formed by casting and the tumblers 5 may be cast with the tumblers or welded to the coil.

Preferably the coil is mechanically held in position in the retort by the shrinkage of the shell onto the coil. This assembly may be made by machining the inner surface of the shell and the outer edges of the turns of the coil and of the tumblers. Such machining may be as long longitudinally as desired. The diameter of the machined surface of the coil and tumblers should not be less than the inside diameter of the machined surface of the shell. When the coil is to be assembled in the shell, the latter is highly heated to cause it to expand, and while so expanding, the coil is slid endwise thereinto. When the shell cools, it will shrink onto thecoil and mechanically hold it in position during the use of the retort.

If desired, the coil may be mechanically connected to the shell by other means. For example, one end of the coil may be welded, as at 41 in FIG. 1, or keyed to the shell or to a tumbler attached to the shell and with or without machining of either the coil or the shell.

In the modification of the present invention shown in FIGS. 4 to 6, the main deviations from the retort of FIG. I are in the tumblers 35 and the notching of the turns 23 of coil 3 as indicated at 37 to receive the tumblers 35. Those tumblers are connected to the inner surface of the shell 31, preferably as by weld metal 39, and are aligned longitudinally of the shell. The tumblers may be spaced apart from one another circumferentially of the drum, as desired, but the notches 37 in the coil are to be so spaced that when the coil is slid endwise in the shell the notches 37 will pass over the tumblers 35 which are fixed in place in the shell. If desired the tumblers 35 may be so spaced that each tumbler will be positioned in a notch 37 when the coil has been finally positioned in the shell, or one or more of the tumblers may be long enough longitudinally of the shell to lie in the notches 37 of two or more coils of the helix. When the tumblers are positioned in notches in the coil, rotation of the shell 31 will result in the tumblers mechanically driving the coil. It will be understood that the coil of FIGS. Al to 6 may be mechanically positioned in and driven by the shell after the manner stated in connection with the retort of FIGS. 1 to 3 if desired, i.e., by carefully machining the inner surface of the shell and the outer edge of the coils and then shrinking the shell onto the coil.

As is noted in FIG. 6, openings 27 may be made in one or more of the turns of the coil as desired and for the purpose explained above.

Having thus described this invention in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains to make and use the same, and having set invention is particularly pointed out and distinctly claimed in what is claimed. it being understood that. equivalents or modifications of or substitutions for, parts of the above specifically described embodiment of the invention may be made without departing from the scope of the invention as set forth in what is claimed.

lclaim:

1. A rotary retort for heating solid articles comprising a cylindrical metal tube open at one end to receive articles to be heated, having an outlet near the other end for discharge of heated articles and having an inlet at said other end for admission of gas to treat articles in the tube, a helical coil mechanically fixed in position in the tube, said coil including a plurality of turns of substantial radial length and spaced apart longitudinally of the tube, and tumblers of substantial radial length extending inwardly from adjacent to the inner surface of the tube.

2. The retort set forth in claim 1 in which the tumblers are aligned lengthwiseof the tube.

3. The retort set forth in claim I in which the tumblers are connected to opposed side surfaces of adjacent turns of the helical coil. I I

4. The retort set forth in claim 1 in which the tumblers are connected to the inner surface ofthe tube. i

5. The retort set forth in claim 4 in which the outer edges of the turns of the helical coil are provided with notches to receive the tumblers.

6. The retort set forth in claim 1 in which the tube has a machined inner surface and the helical coil is mechanically fixed in said tube against said inner surface by contraction of the tube.

7. The retort set forth in claim 1 in which tumblers are at tached to the tube and the,coil is attached to at least one of the tumblers. 

1. A rotary retort for heating solid articles comprising a cylindrical metal tube open at one end to receive articles to be heated, having an outlet near the other end for discharge of heated articles and having an inlet at said other end for admission of gas to treat articles in the tube, a helical coil mechanically fixed in position in the tube, said coil including a plurality of turns of substantial radial length and spaced apart longitudinally of the tube, and tumblers of substantial radial length extending inwardly from adjacent to the inner surface of the tube.
 2. The retort set forth in claim 1 in which the tumblers are aligned lengthwise of the tube.
 3. The retort set forth in claim 1 in which the tumblers are connected to opposed side surfaces of adjacent turns of the helical coil.
 4. The retort set forth in claim 1 in which the tumblers are connected to the inner surface of the tube.
 5. The retort set forth in claim 4 in which the outer edges of the turns of the helical coil are provided with notches to receive the tumblers.
 6. The retort set forth in claim 1 in which the tube has a machined inner surface and the helical coil is mechanically fixed in said tube against said inner surface by contraction of the tube.
 7. The retort set forth in claim 1 in which tumblers are attached to the tube and the coil is attached to at least one of the tumblers. 